Move unique ID generation out to DDGC instance.

Get form ID and action token from this function.
Don't set a new action token on check - this effectively makes it per-session.
Breaking screenshot tracking out into a role for use in other contexts.
Rate limiting in the Comment model.
Cleaning up an error message related to dev deployment.
Allow the error template to be used where we don't want inline errors.

Error message stored in the session (flash won't work for us, too many
parallel requests and such).

Also updated template for custom, generic and log reference messages.
Try/Catch on comment and thread creation for when rate limiting kicks in
Adjusting thread for editing for ScreenshotForm Role.
Disabling comment_rate_limit for testing and dev database deployment.
Moving rate limit check to User model, throws exception in Comment.
Merge pull request #217 from jbarrett/actiontoken-within-formid

Per session token